diff options
Diffstat (limited to '')
| -rw-r--r-- | src/libknot/packet/compr.h | 100 | ||||
| -rw-r--r-- | src/libknot/packet/pkt.c | 826 | ||||
| -rw-r--r-- | src/libknot/packet/pkt.h | 402 | ||||
| -rw-r--r-- | src/libknot/packet/rrset-wire.c | 727 | ||||
| -rw-r--r-- | src/libknot/packet/rrset-wire.h | 73 | ||||
| -rw-r--r-- | src/libknot/packet/wire.h | 980 |
6 files changed, 3108 insertions, 0 deletions
diff --git a/src/libknot/packet/compr.h b/src/libknot/packet/compr.h new file mode 100644 index 0000000..22c4a8e --- /dev/null +++ b/src/libknot/packet/compr.h @@ -0,0 +1,100 @@ +/* Copyright (C) 2018 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz> + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. + */ +/*! + * \file + * + * \brief Name compression API. + * + * \addtogroup pkt + * @{ + */ + +#pragma once + +#include <stdint.h> + +#include "libknot/packet/wire.h" + +/*! \brief Compression hint type. */ +enum knot_compr_hint { + KNOT_COMPR_HINT_NONE = 0, /* No hint. */ + KNOT_COMPR_HINT_NOCOMP = 1, /* Don't compress. */ + KNOT_COMPR_HINT_QNAME = KNOT_WIRE_HEADER_SIZE /* Name is QNAME. */ +}; + +/*! \brief Compression hint array offsets. */ +enum knot_compr_offset { + KNOT_COMPR_HINT_OWNER = 0, /* First element in the array is RR owner. */ + KNOT_COMPR_HINT_RDATA = 1, /* First name in RDATA is at offset 1. */ + KNOT_COMPR_HINT_COUNT = 16 /* Maximum number of stored hints per-RR. */ +}; + +/* + * \note A little bit about how compression hints work. + * + * We're storing a RRSet say 'abcd. CNAME [0]net. [1]com.' (owner=abcd. 2 RRs). + * The owner 'abcd.' is same for both RRs, we put it at the offset 0 in rrinfo.compress_ptr + * The names 'net.' and 'com.' are in the RDATA, therefore go to offsets 1 and 2. + * Now this is useful when solving additionals for example, because we can scan + * rrinfo for this RRSet and we know that 'net.' name is at the hint 1 and that leads + * to packet position N. With that, we just put the pointer in without any calculation. + * This is also useful for positive answers, where we know the RRSet owner is always QNAME. + * All in all, we just remember the positions of written domain names. + */ + +/*! \brief Additional information about RRSet position and compression hints. */ +typedef struct { + uint16_t pos; /* RRSet position in the packet. */ + uint16_t flags; /* RRSet flags. */ + uint16_t compress_ptr[KNOT_COMPR_HINT_COUNT]; /* Array of compr. ptr hints. */ +} knot_rrinfo_t; + +/*! + * \brief Name compression context. + */ +typedef struct knot_compr { + uint8_t *wire; /* Packet wireformat. */ + knot_rrinfo_t *rrinfo; /* Hints for current RRSet. */ + struct { + uint16_t pos; /* Position of current suffix. */ + uint8_t labels; /* Label count of the suffix. */ + } suffix; +} knot_compr_t; + +/*! + * \brief Retrieve compression hint from given offset. + */ +static inline uint16_t knot_compr_hint(const knot_rrinfo_t *info, uint16_t hint_id) +{ + if (hint_id < KNOT_COMPR_HINT_COUNT) { + return info->compress_ptr[hint_id]; + } else { + return KNOT_COMPR_HINT_NONE; + } +} + +/*! + * \brief Store compression hint for given offset. + */ +static inline void knot_compr_hint_set(knot_rrinfo_t *info, uint16_t hint_id, + uint16_t val, uint16_t len) +{ + if ((hint_id < KNOT_COMPR_HINT_COUNT) && (val + len < KNOT_WIRE_PTR_MAX)) { + info->compress_ptr[hint_id] = val; + } +} + +/*! @} */ diff --git a/src/libknot/packet/pkt.c b/src/libknot/packet/pkt.c new file mode 100644 index 0000000..602d70d --- /dev/null +++ b/src/libknot/packet/pkt.c @@ -0,0 +1,826 @@ +/* Copyright (C) 2018 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz> + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <assert.h> +#include <stdlib.h> +#include <stdbool.h> + +#include "libknot/attribute.h" +#include "libknot/packet/pkt.h" +#include "libknot/codes.h" +#include "libknot/descriptor.h" +#include "libknot/errcode.h" +#include "libknot/rrtype/tsig.h" +#include "libknot/tsig-op.h" +#include "libknot/packet/wire.h" +#include "libknot/packet/rrset-wire.h" +#include "libknot/wire.h" +#include "contrib/mempattern.h" +#include "contrib/wire_ctx.h" + +/*! \brief Packet RR array growth step. */ +#define NEXT_RR_ALIGN 16 +#define NEXT_RR_COUNT(count) (((count) / NEXT_RR_ALIGN + 1) * NEXT_RR_ALIGN) + +/*! \brief Scan packet for RRSet existence. */ +static bool pkt_contains(const knot_pkt_t *packet, const knot_rrset_t *rrset) +{ + assert(packet); + assert(rrset); + + for (int i = 0; i < packet->rrset_count; ++i) { + const uint16_t type = packet->rr[i].type; + const knot_rdata_t *data = packet->rr[i].rrs.rdata; + if (type == rrset->type && data == rrset->rrs.rdata) { + return true; + } + } + + return false; +} + +/*! \brief Free all RRSets and reset RRSet count. */ +static void pkt_free_data(knot_pkt_t *pkt) +{ + assert(pkt); + + /* Free RRSets if applicable. */ + for (uint16_t i = 0; i < pkt->rrset_count; ++i) { + if (pkt->rr_info[i].flags & KNOT_PF_FREE) { + knot_rrset_clear(&pkt->rr[i], &pkt->mm); + } + } + pkt->rrset_count = 0; + + /* Free EDNS option positions. */ + mm_free(&pkt->mm, pkt->edns_opts); + pkt->edns_opts = 0; +} + +/*! \brief Allocate new wireformat of given length. */ +static int pkt_wire_alloc(knot_pkt_t *pkt, uint16_t len) +{ + assert(pkt); + + if (len < KNOT_WIRE_HEADER_SIZE) { + return KNOT_ERANGE; + } + + pkt->wire = mm_alloc(&pkt->mm, len); + if (pkt->wire == NULL) { + return KNOT_ENOMEM; + } + + pkt->flags |= KNOT_PF_FREE; + pkt->max_size = len; + + knot_pkt_clear(pkt); + + return KNOT_EOK; +} + +/*! \brief Set packet wireformat to an existing memory. */ +static void pkt_wire_set(knot_pkt_t *pkt, void *wire, uint16_t len) +{ + assert(pkt); + + pkt->wire = wire; + pkt->size = pkt->max_size = len; + pkt->parsed = 0; +} + +/*! \brief Calculate remaining size in the packet. */ +static uint16_t pkt_remaining(knot_pkt_t *pkt) +{ + assert(pkt); + + return pkt->max_size - pkt->size - pkt->reserved; +} + +/*! \brief Return RR count for given section (from wire xxCOUNT in header). */ +static uint16_t pkt_rr_wirecount(knot_pkt_t *pkt, knot_section_t section_id) +{ + assert(pkt); + switch (section_id) { + case KNOT_ANSWER: return knot_wire_get_ancount(pkt->wire); + case KNOT_AUTHORITY: return knot_wire_get_nscount(pkt->wire); + case KNOT_ADDITIONAL: return knot_wire_get_arcount(pkt->wire); + default: assert(0); return 0; + } +} + +/*! \brief Update RR count for given section (wire xxCOUNT in header). */ +static void pkt_rr_wirecount_add(knot_pkt_t *pkt, knot_section_t section_id, + int16_t val) +{ + assert(pkt); + switch (section_id) { + case KNOT_ANSWER: knot_wire_add_ancount(pkt->wire, val); break; + case KNOT_AUTHORITY: knot_wire_add_nscount(pkt->wire, val); break; + case KNOT_ADDITIONAL: knot_wire_add_arcount(pkt->wire, val); break; + } +} + +/*! \brief Reserve enough space in the RR arrays. */ +static int pkt_rr_array_alloc(knot_pkt_t *pkt, uint16_t count) +{ + /* Enough space. */ + if (pkt->rrset_allocd >= count) { + return KNOT_EOK; + } + + /* Allocate rr_info and rr fields to next size. */ + size_t next_size = NEXT_RR_COUNT(count); + knot_rrinfo_t *rr_info = mm_alloc(&pkt->mm, sizeof(knot_rrinfo_t) * next_size); + if (rr_info == NULL) { + return KNOT_ENOMEM; + } + + knot_rrset_t *rr = mm_alloc(&pkt->mm, sizeof(knot_rrset_t) * next_size); + if (rr == NULL) { + mm_free(&pkt->mm, rr_info); + return KNOT_ENOMEM; + } + + /* Copy the old data. */ + memcpy(rr_info, pkt->rr_info, pkt->rrset_allocd * sizeof(knot_rrinfo_t)); + memcpy(rr, pkt->rr, pkt->rrset_allocd * sizeof(knot_rrset_t)); + + /* Reassign and free old data. */ + mm_free(&pkt->mm, pkt->rr); + mm_free(&pkt->mm, pkt->rr_info); + pkt->rr = rr; + pkt->rr_info = rr_info; + pkt->rrset_allocd = next_size; + + return KNOT_EOK; +} + +static void compr_clear(knot_compr_t *compr) +{ + compr->rrinfo = NULL; + compr->suffix.pos = 0; + compr->suffix.labels = 0; +} + +static void compr_init(knot_compr_t *compr, uint8_t *wire) +{ + compr_clear(compr); + compr->wire = wire; +} + +/*! \brief Clear the packet and switch wireformat pointers (possibly allocate new). */ +static int pkt_init(knot_pkt_t *pkt, void *wire, uint16_t len, knot_mm_t *mm) +{ + assert(pkt); + + memset(pkt, 0, sizeof(knot_pkt_t)); + + /* No data to free, set memory context. */ + memcpy(&pkt->mm, mm, sizeof(knot_mm_t)); + + /* Initialize wire. */ + int ret = KNOT_EOK; + if (wire == NULL) { + ret = pkt_wire_alloc(pkt, len); + } else { + pkt_wire_set(pkt, wire, len); + } + + /* Initialize compression context. */ + compr_init(&pkt->compr, pkt->wire); + + return ret; +} + +/*! \brief Reset packet parse state. */ +static void sections_reset(knot_pkt_t *pkt) +{ + pkt->current = KNOT_ANSWER; + memset(pkt->sections, 0, sizeof(pkt->sections)); + (void)knot_pkt_begin(pkt, KNOT_ANSWER); +} + +/*! \brief Allocate new packet using memory context. */ +static knot_pkt_t *pkt_new_mm(void *wire, uint16_t len, knot_mm_t *mm) +{ + assert(mm); + + knot_pkt_t *pkt = mm_alloc(mm, sizeof(knot_pkt_t)); + if (pkt == NULL) { + return NULL; + } + + if (pkt_init(pkt, wire, len, mm) != KNOT_EOK) { + mm_free(mm, pkt); + return NULL; + } + + return pkt; +} + +_public_ +knot_pkt_t *knot_pkt_new(void *wire, uint16_t len, knot_mm_t *mm) +{ + /* Default memory allocator if NULL. */ + knot_mm_t _mm; + if (mm == NULL) { + mm_ctx_init(&_mm); + mm = &_mm; + } + + return pkt_new_mm(wire, len, mm); +} + +static int append_tsig(knot_pkt_t *dst, const knot_pkt_t *src) +{ + /* Check if a wire TSIG is available. */ + if (src->tsig_wire.pos != NULL) { + if (dst->max_size < src->size + src->tsig_wire.len) { + return KNOT_ESPACE; + } + memcpy(dst->wire + dst->size, src->tsig_wire.pos, + src->tsig_wire.len); + dst->size += src->tsig_wire.len; + + /* Increment arcount. */ + knot_wire_set_arcount(dst->wire, + knot_wire_get_arcount(dst->wire) + 1); + } else { + return knot_tsig_append(dst->wire, &dst->size, dst->max_size, + src->tsig_rr); + } + + return KNOT_EOK; +} + +_public_ +int knot_pkt_copy(knot_pkt_t *dst, const knot_pkt_t *src) +{ + if (dst == NULL || src == NULL) { + return KNOT_EINVAL; + } + + if (dst->max_size < src->size) { + return KNOT_ESPACE; + } + memcpy(dst->wire, src->wire, src->size); + dst->size = src->size; + + /* Append TSIG record. */ + if (src->tsig_rr) { + int ret = append_tsig(dst, src); + if (ret != KNOT_EOK) { + return ret; + } + } + + /* Invalidate arrays. */ + dst->rr = NULL; + dst->rr_info = NULL; + dst->rrset_count = 0; + dst->rrset_allocd = 0; + + /* @note This could be done more effectively if needed. */ + return knot_pkt_parse(dst, 0); +} + +static void payload_clear(knot_pkt_t *pkt) +{ + assert(pkt); + + /* Keep question. */ + pkt->parsed = 0; + pkt->reserved = 0; + + /* Free RRSets if applicable. */ + pkt_free_data(pkt); + + /* Reset sections. */ + sections_reset(pkt); + + /* Reset special types. */ + pkt->opt_rr = NULL; + pkt->tsig_rr = NULL; + + /* Reset TSIG wire reference. */ + pkt->tsig_wire.pos = NULL; + pkt->tsig_wire.len = 0; +} + +_public_ +int knot_pkt_init_response(knot_pkt_t *pkt, const knot_pkt_t *query) +{ + if (pkt == NULL || query == NULL) { + return KNOT_EINVAL; + } + + /* Header + question size. */ + size_t base_size = KNOT_WIRE_HEADER_SIZE + knot_pkt_question_size(query); + if (base_size > pkt->max_size) { + return KNOT_ESPACE; + } + + pkt->size = base_size; + memcpy(pkt->wire, query->wire, base_size); + + pkt->qname_size = query->qname_size; + if (query->qname_size == 0) { + /* Reset question count if malformed. */ + knot_wire_set_qdcount(pkt->wire, 0); + } + + /* Update flags and section counters. */ + knot_wire_set_ancount(pkt->wire, 0); + knot_wire_set_nscount(pkt->wire, 0); + knot_wire_set_arcount(pkt->wire, 0); + + knot_wire_set_qr(pkt->wire); + knot_wire_clear_tc(pkt->wire); + knot_wire_clear_ad(pkt->wire); + knot_wire_clear_ra(pkt->wire); + knot_wire_clear_aa(pkt->wire); + knot_wire_clear_z(pkt->wire); + + /* Clear payload. */ + payload_clear(pkt); + + return KNOT_EOK; +} + +_public_ +void knot_pkt_clear(knot_pkt_t *pkt) +{ + if (pkt == NULL) { + return; + } + + /* Reset to header size. */ + pkt->size = KNOT_WIRE_HEADER_SIZE; + memset(pkt->wire, 0, pkt->size); + + /* Clear payload. */ + payload_clear(pkt); + + /* Clear compression context. */ + compr_clear(&pkt->compr); +} + +_public_ +void knot_pkt_free(knot_pkt_t *pkt) +{ + if (pkt == NULL) { + return; + } + + /* Free temporary RRSets. */ + pkt_free_data(pkt); + + /* Free RR/RR info arrays. */ + mm_free(&pkt->mm, pkt->rr); + mm_free(&pkt->mm, pkt->rr_info); + + /* Free the space for wireformat. */ + if (pkt->flags & KNOT_PF_FREE) { + mm_free(&pkt->mm, pkt->wire); + } + + mm_free(&pkt->mm, pkt); +} + +_public_ +int knot_pkt_reserve(knot_pkt_t *pkt, uint16_t size) +{ + if (pkt == NULL) { + return KNOT_EINVAL; + } + + /* Reserve extra space (if possible). */ + if (pkt_remaining(pkt) >= size) { + pkt->reserved += size; + return KNOT_EOK; + } else { + return KNOT_ERANGE; + } +} + +_public_ +int knot_pkt_reclaim(knot_pkt_t *pkt, uint16_t size) +{ + if (pkt == NULL) { + return KNOT_EINVAL; + } + + if (pkt->reserved >= size) { + pkt->reserved -= size; + return KNOT_EOK; + } else { + return KNOT_ERANGE; + } +} + +_public_ +int knot_pkt_begin(knot_pkt_t *pkt, knot_section_t section_id) +{ + if (pkt == NULL || section_id < pkt->current) { + return KNOT_EINVAL; + } + + /* Remember watermark but not on repeated calls. */ + pkt->sections[section_id].pkt = pkt; + if (section_id > pkt->current) { + pkt->sections[section_id].pos = pkt->rrset_count; + } + + pkt->current = section_id; + + return KNOT_EOK; +} + +_public_ +int knot_pkt_put_question(knot_pkt_t *pkt, const knot_dname_t *qname, uint16_t qclass, uint16_t qtype) +{ + if (pkt == NULL || qname == NULL) { + return KNOT_EINVAL; + } + + assert(pkt->size == KNOT_WIRE_HEADER_SIZE); + assert(pkt->rrset_count == 0); + + /* Copy name wireformat. */ + wire_ctx_t wire = wire_ctx_init(pkt->wire, pkt->max_size); + wire_ctx_set_offset(&wire, KNOT_WIRE_HEADER_SIZE); + + int qname_len = knot_dname_to_wire(wire.position, + qname, wire_ctx_available(&wire)); + if (qname_len < 0) { + return qname_len; + } + wire_ctx_skip(&wire, qname_len); + + /* Copy QTYPE & QCLASS */ + wire_ctx_write_u16(&wire, qtype); + wire_ctx_write_u16(&wire, qclass); + + /* Check errors. */ + if (wire.error != KNOT_EOK) { + return wire.error; + } + + /* Update question count and sizes. */ + knot_wire_set_qdcount(pkt->wire, 1); + pkt->size = wire_ctx_offset(&wire); + pkt->qname_size = qname_len; + + /* Start writing ANSWER. */ + return knot_pkt_begin(pkt, KNOT_ANSWER); +} + +_public_ +int knot_pkt_put_rotate(knot_pkt_t *pkt, uint16_t compr_hint, const knot_rrset_t *rr, + uint16_t rotate, uint16_t flags) +{ + if (pkt == NULL || rr == NULL) { + return KNOT_EINVAL; + } + + /* Reserve memory for RR descriptors. */ + int ret = pkt_rr_array_alloc(pkt, pkt->rrset_count + 1); + if (ret != KNOT_EOK) { + return ret; + } + + /* Check for double insertion. */ + if ((flags & KNOT_PF_CHECKDUP) && pkt_contains(pkt, rr)) { + return KNOT_EOK; + } + + knot_rrinfo_t *rrinfo = &pkt->rr_info[pkt->rrset_count]; + memset(rrinfo, 0, sizeof(knot_rrinfo_t)); + rrinfo->pos = pkt->size; + rrinfo->flags = flags; + rrinfo->compress_ptr[0] = compr_hint; + memcpy(pkt->rr + pkt->rrset_count, rr, sizeof(knot_rrset_t)); + + /* Disable compression if no QNAME is available. */ + knot_compr_t *compr = NULL; + if (knot_pkt_qname(pkt) != NULL) { + /* Initialize compression context if it did not happen yet. */ + pkt->compr.rrinfo = rrinfo; + if (pkt->compr.suffix.pos == 0) { + pkt->compr.suffix.pos = KNOT_WIRE_HEADER_SIZE; + pkt->compr.suffix.labels = + knot_dname_labels(pkt->compr.wire + pkt->compr.suffix.pos, + pkt->compr.wire); + } + + compr = &pkt->compr; + } + + uint8_t *pos = pkt->wire + pkt->size; + size_t maxlen = pkt_remaining(pkt); + + /* Write RRSet to wireformat. */ + ret = knot_rrset_to_wire_extra(rr, pos, maxlen, rotate, compr, flags); + if (ret < 0) { + /* Truncate packet if required. */ + if (ret == KNOT_ESPACE && !(flags & KNOT_PF_NOTRUNC)) { + knot_wire_set_tc(pkt->wire); + } + return ret; + } + + size_t len = ret; + uint16_t rr_added = rr->rrs.count; + + /* Keep reference to special types. */ + if (rr->type == KNOT_RRTYPE_OPT) { + pkt->opt_rr = &pkt->rr[pkt->rrset_count]; + } + + if (rr_added > 0) { + pkt->rrset_count += 1; + pkt->sections[pkt->current].count += 1; + pkt->size += len; + pkt_rr_wirecount_add(pkt, pkt->current, rr_added); + } + + return KNOT_EOK; +} + +_public_ +int knot_pkt_parse_question(knot_pkt_t *pkt) +{ + if (pkt == NULL) { + return KNOT_EINVAL; + } + + /* Check at least header size. */ + if (pkt->size < KNOT_WIRE_HEADER_SIZE) { + return KNOT_EMALF; + } + + /* We have at least some DNS header. */ + pkt->parsed = KNOT_WIRE_HEADER_SIZE; + + /* Check QD count. */ + uint16_t qd = knot_wire_get_qdcount(pkt->wire); + if (qd > 1) { + return KNOT_EMALF; + } + + /* No question. */ + if (qd == 0) { + pkt->qname_size = 0; + return KNOT_EOK; + } + + /* Process question. */ + int len = knot_dname_wire_check(pkt->wire + pkt->parsed, + pkt->wire + pkt->size, + NULL /* No compression in QNAME. */); + if (len <= 0) { + return KNOT_EMALF; + } + + /* Check QCLASS/QTYPE size. */ + uint16_t question_size = len + 2 * sizeof(uint16_t); /* QCLASS + QTYPE */ + if (pkt->parsed + question_size > pkt->size) { + return KNOT_EMALF; + } + + pkt->parsed += question_size; + pkt->qname_size = len; + + return KNOT_EOK; +} + +/*! \brief Check constraints (position, uniqueness, validity) for special types + * (TSIG, OPT). + */ +static int check_rr_constraints(knot_pkt_t *pkt, knot_rrset_t *rr, size_t rr_size, + unsigned flags) +{ + switch (rr->type) { + case KNOT_RRTYPE_TSIG: + if (pkt->current != KNOT_ADDITIONAL || pkt->tsig_rr != NULL || + !knot_tsig_rdata_is_ok(rr)) { + return KNOT_EMALF; + } + + /* Strip TSIG RR from wireformat and decrease ARCOUNT. */ + if (!(flags & KNOT_PF_KEEPWIRE)) { + pkt->parsed -= rr_size; + pkt->size -= rr_size; + pkt->tsig_wire.pos = pkt->wire + pkt->parsed; + pkt->tsig_wire.len = rr_size; + knot_wire_set_arcount(pkt->wire, knot_wire_get_arcount(pkt->wire) - 1); + } + + pkt->tsig_rr = rr; + break; + case KNOT_RRTYPE_OPT: + if (pkt->current != KNOT_ADDITIONAL || pkt->opt_rr != NULL || + knot_edns_get_options(rr, &pkt->edns_opts, &pkt->mm) != KNOT_EOK) { + return KNOT_EMALF; + } + + pkt->opt_rr = rr; + break; + default: + break; + } + + return KNOT_EOK; +} + +static int parse_rr(knot_pkt_t *pkt, unsigned flags) +{ + assert(pkt); + + if (pkt->parsed >= pkt->size) { + return KNOT_EFEWDATA; + } + + /* Reserve memory for RR descriptors. */ + int ret = pkt_rr_array_alloc(pkt, pkt->rrset_count + 1); + if (ret != KNOT_EOK) { + return ret; + } + + /* Initialize RR info. */ + memset(&pkt->rr_info[pkt->rrset_count], 0, sizeof(knot_rrinfo_t)); + pkt->rr_info[pkt->rrset_count].pos = pkt->parsed; + pkt->rr_info[pkt->rrset_count].flags = KNOT_PF_FREE; + + /* Parse wire format. */ + size_t rr_size = pkt->parsed; + knot_rrset_t *rr = &pkt->rr[pkt->rrset_count]; + ret = knot_rrset_rr_from_wire(pkt->wire, &pkt->parsed, pkt->size, + rr, &pkt->mm, !(flags & KNOT_PF_NOCANON)); + if (ret != KNOT_EOK) { + return ret; + } + + /* Calculate parsed RR size from before/after parsing. */ + rr_size = (pkt->parsed - rr_size); + + /* Update packet RRSet count. */ + ++pkt->rrset_count; + ++pkt->sections[pkt->current].count; + + /* Check special RRs (OPT and TSIG). */ + return check_rr_constraints(pkt, rr, rr_size, flags); +} + +static int parse_section(knot_pkt_t *pkt, unsigned flags) +{ + assert(pkt); + + uint16_t rr_parsed = 0; + uint16_t rr_count = pkt_rr_wirecount(pkt, pkt->current); + + /* Parse all RRs belonging to the section. */ + for (rr_parsed = 0; rr_parsed < rr_count; ++rr_parsed) { + int ret = parse_rr(pkt, flags); + if (ret != KNOT_EOK) { + return ret; + } + } + + return KNOT_EOK; +} + +static int parse_payload(knot_pkt_t *pkt, unsigned flags) +{ + assert(pkt); + assert(pkt->wire); + assert(pkt->size > 0); + + /* Reserve memory in advance to avoid resizing. */ + size_t rr_count = knot_wire_get_ancount(pkt->wire) + + knot_wire_get_nscount(pkt->wire) + + knot_wire_get_arcount(pkt->wire); + + if (rr_count > pkt->size / KNOT_WIRE_RR_MIN_SIZE) { + return KNOT_EMALF; + } + + int ret = pkt_rr_array_alloc(pkt, rr_count); + if (ret != KNOT_EOK) { + return ret; + } + + for (knot_section_t i = KNOT_ANSWER; i <= KNOT_ADDITIONAL; ++i) { + ret = knot_pkt_begin(pkt, i); + if (ret != KNOT_EOK) { + return ret; + } + ret = parse_section(pkt, flags); + if (ret != KNOT_EOK) { + return ret; + } + } + + /* TSIG must be last record of AR if present. */ + const knot_pktsection_t *ar = knot_pkt_section(pkt, KNOT_ADDITIONAL); + if (pkt->tsig_rr != NULL) { + const knot_rrset_t *last_rr = knot_pkt_rr(ar, ar->count - 1); + if (ar->count > 0 && pkt->tsig_rr->rrs.rdata != last_rr->rrs.rdata) { + return KNOT_EMALF; + } + } + + /* Check for trailing garbage. */ + if (pkt->parsed < pkt->size) { + return KNOT_ETRAIL; + } + + return KNOT_EOK; +} + +_public_ +int knot_pkt_parse(knot_pkt_t *pkt, unsigned flags) +{ + if (pkt == NULL) { + return KNOT_EINVAL; + } + + /* Reset parse state. */ + sections_reset(pkt); + + int ret = knot_pkt_parse_question(pkt); + if (ret == KNOT_EOK) { + ret = parse_payload(pkt, flags); + } + + return ret; +} + +_public_ +uint16_t knot_pkt_ext_rcode(const knot_pkt_t *pkt) +{ + if (pkt == NULL) { + return 0; + } + + /* Get header RCODE. */ + uint16_t rcode = knot_wire_get_rcode(pkt->wire); + + /* Update to extended RCODE if EDNS is available. */ + if (pkt->opt_rr != NULL) { + uint8_t opt_rcode = knot_edns_get_ext_rcode(pkt->opt_rr); + rcode = knot_edns_whole_rcode(opt_rcode, rcode); + } + + /* Return if not NOTAUTH. */ + if (rcode != KNOT_RCODE_NOTAUTH) { + return rcode; + } + + /* Get TSIG RCODE. */ + uint16_t tsig_rcode = KNOT_RCODE_NOERROR; + if (pkt->tsig_rr != NULL) { + tsig_rcode = knot_tsig_rdata_error(pkt->tsig_rr); + } + + /* Return proper RCODE. */ + if (tsig_rcode != KNOT_RCODE_NOERROR) { + return tsig_rcode; + } else { + return rcode; + } +} + +_public_ +const char *knot_pkt_ext_rcode_name(const knot_pkt_t *pkt) +{ + if (pkt == NULL) { + return ""; + } + + uint16_t rcode = knot_pkt_ext_rcode(pkt); + + const knot_lookup_t *item = NULL; + if (pkt->tsig_rr != NULL) { + item = knot_lookup_by_id(knot_tsig_rcode_names, rcode); + } + if (item == NULL) { + item = knot_lookup_by_id(knot_rcode_names, rcode); + } + + return (item != NULL) ? item->name : ""; +} diff --git a/src/libknot/packet/pkt.h b/src/libknot/packet/pkt.h new file mode 100644 index 0000000..a105d9f --- /dev/null +++ b/src/libknot/packet/pkt.h @@ -0,0 +1,402 @@ +/* Copyright (C) 2018 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz> + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. + */ +/*! + * \file + * + * \brief Structure for holding DNS packet data and metadata. + * + * \addtogroup pkt + * @{ + */ + +#pragma once + +#include <assert.h> +#include <stdint.h> + +#include "libknot/consts.h" +#include "libknot/dname.h" +#include "libknot/mm_ctx.h" +#include "libknot/rrset.h" +#include "libknot/rrtype/opt.h" +#include "libknot/packet/wire.h" +#include "libknot/packet/compr.h" +#include "libknot/wire.h" + +/* Number of packet sections (ANSWER, AUTHORITY, ADDITIONAL). */ +#define KNOT_PKT_SECTIONS 3 + +/*! + * \brief Packet flags. + */ +enum { + KNOT_PF_NULL = 0 << 0, /*!< No flags. */ + KNOT_PF_FREE = 1 << 1, /*!< Free with packet. */ + KNOT_PF_NOTRUNC = 1 << 2, /*!< Don't truncate. */ + KNOT_PF_CHECKDUP = 1 << 3, /*!< Check for duplicates. */ + KNOT_PF_KEEPWIRE = 1 << 4, /*!< Keep wireformat untouched when parsing. */ + KNOT_PF_NOCANON = 1 << 5, /*!< Don't canonicalize rrsets during parsing. */ + KNOT_PF_ORIGTTL = 1 << 6, /*!< Write RRSIGs with their original TTL. */ +}; + +typedef struct knot_pkt knot_pkt_t; + +/*! + * \brief Packet section. + * Points to RRSet and RRSet info arrays in the packet. + * This structure is required for random access to packet sections. + */ +typedef struct { + knot_pkt_t *pkt; /*!< Owner. */ + uint16_t pos; /*!< Position in the rr/rrinfo fields in packet. */ + uint16_t count; /*!< Number of RRSets in this section. */ +} knot_pktsection_t; + +/*! + * \brief Structure representing a DNS packet. + */ +struct knot_pkt { + uint8_t *wire; /*!< Wire format of the packet. */ + size_t size; /*!< Current wire size of the packet. */ + size_t max_size; /*!< Maximum allowed size of the packet. */ + size_t parsed; /*!< Parsed size. */ + uint16_t reserved; /*!< Reserved space. */ + uint16_t qname_size; /*!< QNAME size. */ + uint16_t rrset_count; /*!< Packet RRSet count. */ + uint16_t flags; /*!< Packet flags. */ + + knot_rrset_t *opt_rr; /*!< OPT RR included in the packet. */ + knot_rrset_t *tsig_rr; /*!< TSIG RR stored in the packet. */ + + /*! EDNS option positions in the wire (if parsed from wire). */ + knot_edns_options_t *edns_opts; + + /*! TSIG RR position in the wire (if parsed from wire). */ + struct { + uint8_t *pos; + size_t len; + } tsig_wire; + + /* Packet sections. */ + knot_section_t current; + knot_pktsection_t sections[KNOT_PKT_SECTIONS]; + + /* Packet RRSet (meta)data. */ + size_t rrset_allocd; + knot_rrinfo_t *rr_info; + knot_rrset_t *rr; + + knot_mm_t mm; /*!< Memory allocation context. */ + + knot_compr_t compr; /*!< Compression context. */ +}; + +/*! + * \brief Create new packet over existing memory, or allocate new from memory context. + * + * \note Packet is allocated from given memory context. + * + * \param wire If NULL, memory of 'len' size shall be allocated. + * Otherwise pointer is used for the wire format of the packet. + * \param len Wire format length. + * \param mm Memory context (NULL for default). + * \return New packet or NULL. + */ +knot_pkt_t *knot_pkt_new(void *wire, uint16_t len, knot_mm_t *mm); + +/*! + * \brief Copy packet. + * + * \note Current implementation is not very efficient, as it re-parses the wire. + * + * \param dst Target packet. + * \param src Source packet. + * + * \return new packet or NULL + */ +int knot_pkt_copy(knot_pkt_t *dst, const knot_pkt_t *src); + +/*! + * \brief Initialized response from query packet. + * + * \note Question is not checked, it is expected to be checked already. + * + * \param pkt Given packet. + * \param query Query. + * \return KNOT_EOK, KNOT_EINVAL, KNOT_ESPACE + */ +int knot_pkt_init_response(knot_pkt_t *pkt, const knot_pkt_t *query); + +/*! \brief Reinitialize packet for another use. */ +void knot_pkt_clear(knot_pkt_t *pkt); + +/*! \brief Begone you foul creature of the underworld. */ +void knot_pkt_free(knot_pkt_t *pkt); + +/*! + * \brief Reserve an arbitrary amount of space in the packet. + * + * \return KNOT_EOK + * \return KNOT_ERANGE if size can't be reserved + */ +int knot_pkt_reserve(knot_pkt_t *pkt, uint16_t size); + +/*! + * \brief Reclaim reserved size. + * + * \return KNOT_EOK + * \return KNOT_ERANGE if size can't be reclaimed + */ +int knot_pkt_reclaim(knot_pkt_t *pkt, uint16_t size); + +/* + * Packet QUESTION accessors. + */ +static inline uint16_t knot_pkt_question_size(const knot_pkt_t *pkt) +{ + if (pkt == NULL || pkt->qname_size == 0) { + return 0; + } + + return pkt->qname_size + 2 * sizeof(uint16_t); +} + +static inline knot_dname_t *knot_pkt_qname(const knot_pkt_t *pkt) +{ + if (pkt == NULL || pkt->qname_size == 0) { + return NULL; + } + + return pkt->wire + KNOT_WIRE_HEADER_SIZE; +} + +static inline uint16_t knot_pkt_qtype(const knot_pkt_t *pkt) +{ + if (pkt == NULL || pkt->qname_size == 0) { + return 0; + } + + unsigned off = KNOT_WIRE_HEADER_SIZE + pkt->qname_size; + return knot_wire_read_u16(pkt->wire + off); +} + +static inline uint16_t knot_pkt_qclass(const knot_pkt_t *pkt) +{ + if (pkt == NULL || pkt->qname_size == 0) { + return 0; + } + + unsigned off = KNOT_WIRE_HEADER_SIZE + pkt->qname_size + sizeof(uint16_t); + return knot_wire_read_u16(pkt->wire + off); +} + +/* + * Packet writing API. + */ + +/*! + * \brief Begin reading/writing packet section. + * + * \note You must proceed in the natural order (ANSWER, AUTHORITY, ADDITIONAL). + * + * \param pkt + * \param section_id + * \return KNOT_EOK or KNOT_EINVAL + */ +int knot_pkt_begin(knot_pkt_t *pkt, knot_section_t section_id); + +/*! + * \brief Put QUESTION in the packet. + * + * \note Since we support QD=1 only, QUESTION is a special type of packet section. + * \note Must not be used after putting RRsets into the packet. + * + * \param pkt + * \param qname + * \param qclass + * \param qtype + * \return KNOT_EOK or various errors + */ +int knot_pkt_put_question(knot_pkt_t *pkt, const knot_dname_t *qname, + uint16_t qclass, uint16_t qtype); + +/*! + * \brief Put RRSet into packet. + * + * \note See compr.h for description on how compression hints work. + * \note Available flags: PF_FREE, KNOT_PF_CHECKDUP, KNOT_PF_NOTRUNC + * + * \param pkt + * \param compr_hint Compression hint, see enum knot_compr_hint or absolute + * position. + * \param rr Given RRSet. + * \param rotate Rotate the RRSet order by this count. + * \param flags RRSet flags (set PF_FREE if you want RRSet to be freed + * with the packet). + * + * \return KNOT_EOK, KNOT_ESPACE, various errors + */ +int knot_pkt_put_rotate(knot_pkt_t *pkt, uint16_t compr_hint, const knot_rrset_t *rr, + uint16_t rotate, uint16_t flags); + +/*! \brief Same as knot_pkt_put_rotate but without rrset rotation. */ +static inline int knot_pkt_put(knot_pkt_t *pkt, uint16_t compr_hint, + const knot_rrset_t *rr, uint16_t flags) +{ + return knot_pkt_put_rotate(pkt, compr_hint, rr, 0, flags); +} + +/*! \brief Get description of the given packet section. */ +static inline const knot_pktsection_t *knot_pkt_section(const knot_pkt_t *pkt, + knot_section_t section_id) +{ + assert(pkt); + return &pkt->sections[section_id]; +} + +/*! \brief Get RRSet from the packet section. */ +static inline const knot_rrset_t *knot_pkt_rr(const knot_pktsection_t *section, + uint16_t i) +{ + assert(section); + return section->pkt->rr + section->pos + i; +} + +/*! \brief Get RRSet offset in the packet wire. */ +static inline uint16_t knot_pkt_rr_offset(const knot_pktsection_t *section, + uint16_t i) +{ + assert(section); + return section->pkt->rr_info[section->pos + i].pos; +} + +/* + * Packet parsing API. + */ + +/*! + * \brief Parse both packet question and payload. + * + * Parses both QUESTION and all packet sections, + * includes semantic checks over specific RRs (TSIG, OPT). + * + * \note If KNOT_PF_KEEPWIRE is set, TSIG RR is not stripped from the wire + * and is processed as any other RR. + * + * \param pkt Given packet. + * \param flags Parsing flags (allowed KNOT_PF_KEEPWIRE) + * + * \retval KNOT_EOK if success. + * \retval KNOT_ETRAIL if success but with some trailing data. + * \retval KNOT_EMALF and other errors. + */ +int knot_pkt_parse(knot_pkt_t *pkt, unsigned flags); + +/*! + * \brief Parse packet header and a QUESTION section. + */ +int knot_pkt_parse_question(knot_pkt_t *pkt); + +/*! + * \brief Get packet extended RCODE. + * + * Extended RCODE is created by considering TSIG RCODE, EDNS RCODE and + * DNS Header RCODE. (See RFC 6895, Section 2.3). + * + * \param pkt Packet to get the response code from. + * + * \return Whole extended RCODE (0 if pkt == NULL). + */ +uint16_t knot_pkt_ext_rcode(const knot_pkt_t *pkt); + +/*! + * \brief Get packet extended RCODE name. + * + * The packet parameter is important as the name depends on TSIG. + * + * \param pkt Packet to get the response code from. + * + * \return RCODE name (or empty string if not known). + */ +const char *knot_pkt_ext_rcode_name(const knot_pkt_t *pkt); + +/*! + * \brief Checks if there is an OPT RR in the packet. + */ +static inline bool knot_pkt_has_edns(const knot_pkt_t *pkt) +{ + assert(pkt); + return pkt->opt_rr != NULL; +} + +/*! + * \brief Checks if TSIG is present. + */ +static inline bool knot_pkt_has_tsig(const knot_pkt_t *pkt) +{ + assert(pkt); + return pkt->tsig_rr != NULL; +} + +/*! + * \brief Checks if DO bit is set in the packet's OPT RR. + */ +static inline bool knot_pkt_has_dnssec(const knot_pkt_t *pkt) +{ + assert(pkt); + return knot_pkt_has_edns(pkt) && knot_edns_do(pkt->opt_rr); +} + +/*! + * \brief Get specific EDNS option from a parsed packet. + */ +static inline uint8_t *knot_pkt_edns_option(const knot_pkt_t *pkt, uint16_t code) +{ + assert(pkt); + if (pkt->edns_opts != NULL && code <= KNOT_EDNS_MAX_OPTION_CODE) { + return pkt->edns_opts->ptr[code]; + } else { + return NULL; + } +} + +/*! + * \brief Computes a reasonable Padding data length for a given packet and opt RR. + * + * \param pkt DNS Packet prepared and otherwise ready to go, no OPT yet added. + * \param opt_rr OPT RR, not yet including padding. + * + * \return Required padding length or -1 if padding not required. + */ +static inline int knot_pkt_default_padding_size(const knot_pkt_t *pkt, + const knot_rrset_t *opt_rr) +{ + if (knot_wire_get_qr(pkt->wire)) { + return knot_edns_alignment_size(pkt->size, knot_rrset_size(opt_rr), + KNOT_EDNS_ALIGNMENT_RESPONSE_DEFAULT); + } else { + return knot_edns_alignment_size(pkt->size, knot_rrset_size(opt_rr), + KNOT_EDNS_ALIGNMENT_QUERY_DEFALT); + } +} + +static inline size_t knot_pkt_size(const knot_pkt_t *pkt) +{ + assert(pkt); + return pkt->size + (knot_pkt_has_tsig(pkt) ? pkt->tsig_wire.len : 0); +} + +/*! @} */ diff --git a/src/libknot/packet/rrset-wire.c b/src/libknot/packet/rrset-wire.c new file mode 100644 index 0000000..dadadd5 --- /dev/null +++ b/src/libknot/packet/rrset-wire.c @@ -0,0 +1,727 @@ +/* Copyright (C) 2018 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz> + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <assert.h> + +#include "libknot/attribute.h" +#include "libknot/consts.h" +#include "libknot/descriptor.h" +#include "libknot/packet/pkt.h" +#include "libknot/packet/rrset-wire.h" +#include "libknot/rrtype/naptr.h" +#include "libknot/rrtype/rrsig.h" +#include "contrib/macros.h" +#include "contrib/mempattern.h" +#include "contrib/tolower.h" +#include "contrib/wire_ctx.h" + +/*! + * \brief Get maximal size of a domain name in a wire with given capacity. + */ +static uint16_t dname_max(size_t wire_avail) +{ + return MIN(wire_avail, KNOT_DNAME_MAXLEN); +} + +/*! + * \brief Compares two domain name labels. + * + * \param label1 First label. + * \param label2 Second label (may be in upper-case). + * + * \retval true if the labels are identical + * \retval false if the labels are NOT identical + */ +static bool label_is_equal(const uint8_t *label1, const uint8_t *label2) +{ + assert(label1 && label2); + + if (*label1 != *label2) { + return false; + } + + uint8_t len = *label1; + for (uint8_t i = 1; i <= len; i++) { + if (label1[i] != knot_tolower(label2[i])) { + return false; + } + } + + return true; +} + +/*! + * Case insensitive comparison of two dnames in wire format. + * The second name may be compressed in a supplied wire. + */ +static bool dname_equal_wire(const knot_dname_t *d1, const knot_dname_t *d2, + const uint8_t *wire) +{ + assert(d1); + assert(d2); + + d2 = knot_wire_seek_label(d2, wire); + + while (*d1 != '\0' || *d2 != '\0') { + if (!label_is_equal(d1, d2)) { + return false; + } + d1 = knot_wire_next_label(d1, NULL); + d2 = knot_wire_next_label(d2, wire); + } + + return true; +} + +static uint16_t compr_get_ptr(knot_compr_t *compr, uint16_t hint) +{ + if (compr == NULL) { + return 0; + } + + return knot_compr_hint(compr->rrinfo, hint); +} + +static void compr_set_ptr(knot_compr_t *compr, uint16_t hint, + const uint8_t *written_at, uint16_t written_size) +{ + if (compr == NULL) { + return; + } + + assert(written_at >= compr->wire); + + uint16_t offset = written_at - compr->wire; + + knot_compr_hint_set(compr->rrinfo, hint, offset, written_size); +} + +static int write_rdata_fixed(const uint8_t **src, size_t *src_avail, + uint8_t **dst, size_t *dst_avail, size_t size) +{ + assert(src && *src); + assert(src_avail); + assert(dst && *dst); + assert(dst_avail); + + // Check input/output buffer boundaries. + if (size > *src_avail) { + return KNOT_EMALF; + } + + if (size > *dst_avail) { + return KNOT_ESPACE; + } + + // Data binary copy. + memcpy(*dst, *src, size); + + // Update buffers. + *src += size; + *src_avail -= size; + + *dst += size; + *dst_avail -= size; + + return KNOT_EOK; +} + +static int write_rdata_naptr_header(const uint8_t **src, size_t *src_avail, + uint8_t **dst, size_t *dst_avail) +{ + assert(src && *src); + assert(src_avail); + assert(dst && *dst); + assert(dst_avail); + + int ret = knot_naptr_header_size(*src, *src + *src_avail); + if (ret < 0) { + return ret; + } + + // Copy the data. + return write_rdata_fixed(src, src_avail, dst, dst_avail, ret); +} + +/*! \brief Helper for \ref compr_put_dname, writes label(s) with size checks. */ +#define WRITE_LABEL(dst, written, label, max, len) \ + if ((written) + (len) > (max)) { \ + return KNOT_ESPACE; \ + } else { \ + memcpy((dst) + (written), (label), (len)); \ + written += (len); \ + } + +/*! + * \brief Write compressed domain name to the destination wire. + * + * \param dname Name to be written. + * \param dst Destination wire. + * \param max Maximum number of bytes available. + * \param compr Compression context (NULL for no compression) + * \return Number of written bytes or an error. + */ +static int compr_put_dname(const knot_dname_t *dname, uint8_t *dst, uint16_t max, + knot_compr_t *compr) +{ + assert(dname && dst); + + // Write uncompressible names directly (zero label dname). + if (compr == NULL || *dname == '\0') { + return knot_dname_to_wire(dst, dname, max); + } + + // Get number of labels (should not be a zero label dname). + size_t name_labels = knot_dname_labels(dname, NULL); + assert(name_labels > 0); + + // Suffix must not be longer than whole name. + const knot_dname_t *suffix = compr->wire + compr->suffix.pos; + int suffix_labels = compr->suffix.labels; + while (suffix_labels > name_labels) { + suffix = knot_wire_next_label(suffix, compr->wire); + --suffix_labels; + } + + // Suffix is shorter than name, write labels until aligned. + uint8_t orig_labels = name_labels; + uint16_t written = 0; + while (name_labels > suffix_labels) { + WRITE_LABEL(dst, written, dname, max, (*dname + 1)); + dname = knot_wire_next_label(dname, NULL); + --name_labels; + } + + // Label count is now equal. + assert(name_labels == suffix_labels); + const knot_dname_t *match_begin = dname; + const knot_dname_t *compr_ptr = suffix; + while (dname[0] != '\0') { + // Next labels. + const knot_dname_t *next_dname = knot_wire_next_label(dname, NULL); + const knot_dname_t *next_suffix = knot_wire_next_label(suffix, compr->wire); + + // Two labels match, extend suffix length. + if (!label_is_equal(dname, suffix)) { + // If they don't match, write unmatched labels. + uint16_t mismatch_len = (dname - match_begin) + (*dname + 1); + WRITE_LABEL(dst, written, match_begin, max, mismatch_len); + // Start new potential match. + match_begin = next_dname; + compr_ptr = next_suffix; + } + + // Jump to next labels. + dname = next_dname; + suffix = next_suffix; + } + + // If match begins at the end of the name, write '\0' label. + if (match_begin == dname) { + WRITE_LABEL(dst, written, dname, max, 1); + } else { + // Match covers >0 labels, write out compression pointer. + if (written + sizeof(uint16_t) > max) { + return KNOT_ESPACE; + } + knot_wire_put_pointer(dst + written, compr_ptr - compr->wire); + written += sizeof(uint16_t); + } + + assert(dst >= compr->wire); + size_t wire_pos = dst - compr->wire; + assert(wire_pos < KNOT_WIRE_MAX_PKTSIZE); + + // Heuristics - expect similar names are grouped together. + if (written > sizeof(uint16_t) && wire_pos + written < KNOT_WIRE_PTR_MAX) { + compr->suffix.pos = wire_pos; + compr->suffix.labels = orig_labels; + } + + return written; +} + +#define WRITE_OWNER_CHECK(size, dst_avail) \ + if ((size) > *(dst_avail)) { \ + return KNOT_ESPACE; \ + } + +#define WRITE_OWNER_INCR(dst, dst_avail, size) \ + *(dst) += (size); \ + *(dst_avail) -= (size); + +static int write_owner(const knot_rrset_t *rrset, uint8_t **dst, size_t *dst_avail, + knot_compr_t *compr) +{ + assert(rrset); + assert(dst && *dst); + assert(dst_avail); + + // Check for zero label owner (don't compress). + uint16_t owner_pointer = 0; + if (*rrset->owner != '\0') { + owner_pointer = compr_get_ptr(compr, KNOT_COMPR_HINT_OWNER); + } + + // Write result. + if (owner_pointer > 0) { + WRITE_OWNER_CHECK(sizeof(uint16_t), dst_avail); + knot_wire_put_pointer(*dst, owner_pointer); + WRITE_OWNER_INCR(dst, dst_avail, sizeof(uint16_t)); + // Check for coincidence with previous RR set. + } else if (compr != NULL && compr->suffix.pos != 0 && *rrset->owner != '\0' && + dname_equal_wire(rrset->owner, compr->wire + compr->suffix.pos, + compr->wire)) { + WRITE_OWNER_CHECK(sizeof(uint16_t), dst_avail); + knot_wire_put_pointer(*dst, compr->suffix.pos); + compr_set_ptr(compr, KNOT_COMPR_HINT_OWNER, + compr->wire + compr->suffix.pos, + knot_dname_size(rrset->owner)); + WRITE_OWNER_INCR(dst, dst_avail, sizeof(uint16_t)); + } else { + if (compr != NULL) { + compr->suffix.pos = KNOT_WIRE_HEADER_SIZE; + compr->suffix.labels = + knot_dname_labels(compr->wire + compr->suffix.pos, + compr->wire); + } + // WRITE_OWNER_CHECK not needed, compr_put_dname has a check. + int written = compr_put_dname(rrset->owner, *dst, + dname_max(*dst_avail), compr); + if (written < 0) { + return written; + } + + compr_set_ptr(compr, KNOT_COMPR_HINT_OWNER, *dst, written); + WRITE_OWNER_INCR(dst, dst_avail, written); + } + + return KNOT_EOK; +} + +static int write_fixed_header(const knot_rrset_t *rrset, uint16_t rrset_index, + uint8_t **dst, size_t *dst_avail, uint16_t flags) +{ + assert(rrset); + assert(rrset_index < rrset->rrs.count); + assert(dst && *dst); + assert(dst_avail); + + // Write header. + wire_ctx_t write = wire_ctx_init(*dst, *dst_avail); + + wire_ctx_write_u16(&write, rrset->type); + wire_ctx_write_u16(&write, rrset->rclass); + + if ((flags & KNOT_PF_ORIGTTL) && rrset->type == KNOT_RRTYPE_RRSIG) { + const knot_rdata_t *rdata = knot_rdataset_at(&rrset->rrs, rrset_index); + wire_ctx_write_u32(&write, knot_rrsig_original_ttl(rdata)); + } else { + wire_ctx_write_u32(&write, rrset->ttl); + } + + // Check write. + if (write.error != KNOT_EOK) { + return write.error; + } + + // Update buffer. + *dst = write.position; + *dst_avail = wire_ctx_available(&write); + + return KNOT_EOK; +} + +static int compress_rdata_dname(const uint8_t **src, size_t *src_avail, + uint8_t **dst, size_t *dst_avail, + knot_compr_t *put_compr, knot_compr_t *compr, + uint16_t hint) +{ + assert(src && *src); + assert(src_avail); + assert(dst && *dst); + assert(dst_avail); + + // Source domain name. + const knot_dname_t *dname = *src; + size_t dname_size = knot_dname_size(dname); + + // Output domain name. + int written = compr_put_dname(dname, *dst, dname_max(*dst_avail), put_compr); + if (written < 0) { + return written; + } + + // Update compression hints. + if (compr_get_ptr(compr, hint) == 0) { + compr_set_ptr(compr, hint, *dst, written); + } + + // Update buffers. + *dst += written; + *dst_avail -= written; + + *src += dname_size; + *src_avail -= dname_size; + + return KNOT_EOK; +} + +static int rdata_traverse_write(const uint8_t **src, size_t *src_avail, + uint8_t **dst, size_t *dst_avail, + const knot_rdata_descriptor_t *desc, + knot_compr_t *compr, uint16_t hint) +{ + for (const int *type = desc->block_types; *type != KNOT_RDATA_WF_END; type++) { + int ret; + knot_compr_t *put_compr = NULL; + switch (*type) { + case KNOT_RDATA_WF_COMPRESSIBLE_DNAME: + put_compr = compr; + // FALLTHROUGH + case KNOT_RDATA_WF_DECOMPRESSIBLE_DNAME: + case KNOT_RDATA_WF_FIXED_DNAME: + ret = compress_rdata_dname(src, src_avail, dst, dst_avail, + put_compr, compr, hint); + break; + case KNOT_RDATA_WF_NAPTR_HEADER: + ret = write_rdata_naptr_header(src, src_avail, dst, dst_avail); + break; + case KNOT_RDATA_WF_REMAINDER: + ret = write_rdata_fixed(src, src_avail, dst, dst_avail, *src_avail); + break; + default: + // Fixed size block. + assert(*type > 0); + ret = write_rdata_fixed(src, src_avail, dst, dst_avail, *type); + break; + } + if (ret != KNOT_EOK) { + return ret; + } + } + + return KNOT_EOK; +} + +static int write_rdata(const knot_rrset_t *rrset, uint16_t rrset_index, + uint8_t **dst, size_t *dst_avail, knot_compr_t *compr) +{ + assert(rrset); + assert(rrset_index < rrset->rrs.count); + assert(dst && *dst); + assert(dst_avail); + + const knot_rdata_t *rdata = knot_rdataset_at(&rrset->rrs, rrset_index); + + // Reserve space for RDLENGTH. + if (sizeof(uint16_t) > *dst_avail) { + return KNOT_ESPACE; + } + + uint8_t *wire_rdlength = *dst; + *dst += sizeof(uint16_t); + *dst_avail -= sizeof(uint16_t); + uint8_t *wire_rdata_begin = *dst; + + // Write RDATA. + const uint8_t *src = rdata->data; + size_t src_avail = rdata->len; + if (src_avail > 0) { + // Only write non-empty data. + const knot_rdata_descriptor_t *desc = + knot_get_rdata_descriptor(rrset->type); + int ret = rdata_traverse_write(&src, &src_avail, dst, dst_avail, + desc, compr, KNOT_COMPR_HINT_RDATA + rrset_index); + if (ret != KNOT_EOK) { + return ret; + } + } + + // Check for trailing data in the message. + if (src_avail > 0) { + return KNOT_EMALF; + } + + // Write final RDLENGTH. + size_t rdlength = *dst - wire_rdata_begin; + knot_wire_write_u16(wire_rdlength, rdlength); + + return KNOT_EOK; +} + +static int write_rr(const knot_rrset_t *rrset, uint16_t rrset_index, uint8_t **dst, + size_t *dst_avail, knot_compr_t *compr, uint16_t flags) +{ + int ret = write_owner(rrset, dst, dst_avail, compr); + if (ret != KNOT_EOK) { + return ret; + } + + ret = write_fixed_header(rrset, rrset_index, dst, dst_avail, flags); + if (ret != KNOT_EOK) { + return ret; + } + + return write_rdata(rrset, rrset_index, dst, dst_avail, compr); +} + +_public_ +int knot_rrset_to_wire_extra(const knot_rrset_t *rrset, uint8_t *wire, + uint16_t max_size, uint16_t rotate, + knot_compr_t *compr, uint16_t flags) +{ + if (rrset == NULL || wire == NULL) { + return KNOT_EINVAL; + } + if (rrset->rrs.count == 0) { + return 0; + } + if (rotate != 0) { + rotate %= rrset->rrs.count; + } + + uint8_t *write = wire; + size_t capacity = max_size; + + uint16_t count = rrset->rrs.count; + for (uint16_t i = rotate; i < count + rotate; i++) { + uint16_t pos = (i < count) ? i : (i - count); + int ret = write_rr(rrset, pos, &write, &capacity, compr, flags); + if (ret != KNOT_EOK) { + return ret; + } + } + + return write - wire; +} + +_public_ +int knot_rrset_to_wire_rotate(const knot_rrset_t *rrset, uint8_t *wire, + uint16_t max_size, uint16_t rotate, + knot_compr_t *compr) +{ + return knot_rrset_to_wire_extra(rrset, wire, max_size, rotate, compr, 0); +} + +static int parse_header(const uint8_t *wire, size_t *pos, size_t pkt_size, + knot_mm_t *mm, knot_rrset_t *rrset, uint16_t *rdlen) +{ + assert(wire); + assert(pos); + assert(rrset); + assert(rdlen); + + wire_ctx_t src = wire_ctx_init_const(wire, pkt_size); + wire_ctx_set_offset(&src, *pos); + + int compr_size = knot_dname_wire_check(src.position, wire + pkt_size, wire); + if (compr_size <= 0) { + return KNOT_EMALF; + } + + uint8_t buff[KNOT_DNAME_MAXLEN]; + int decompr_size = knot_dname_unpack(buff, src.position, sizeof(buff), wire); + if (decompr_size <= 0) { + return KNOT_EMALF; + } + + knot_dname_t *owner = mm_alloc(mm, decompr_size); + if (owner == NULL) { + return KNOT_ENOMEM; + } + memcpy(owner, buff, decompr_size); + wire_ctx_skip(&src, compr_size); + + uint16_t type = wire_ctx_read_u16(&src); + uint16_t rclass = wire_ctx_read_u16(&src); + uint32_t ttl = wire_ctx_read_u32(&src); + *rdlen = wire_ctx_read_u16(&src); + + if (src.error != KNOT_EOK) { + knot_dname_free(owner, mm); + return KNOT_EMALF; + } + + if (wire_ctx_available(&src) < *rdlen) { + knot_dname_free(owner, mm); + return KNOT_EMALF; + } + + *pos = wire_ctx_offset(&src); + + knot_rrset_init(rrset, owner, type, rclass, ttl); + + return KNOT_EOK; +} + +static int decompress_rdata_dname(const uint8_t **src, size_t *src_avail, + uint8_t **dst, size_t *dst_avail, + const uint8_t *pkt_wire) +{ + assert(src && *src); + assert(src_avail); + assert(dst && *dst); + assert(dst_avail); + + int compr_size = knot_dname_wire_check(*src, *src + *src_avail, pkt_wire); + if (compr_size <= 0) { + return compr_size; + } + + int decompr_size = knot_dname_unpack(*dst, *src, *dst_avail, pkt_wire); + if (decompr_size <= 0) { + return decompr_size; + } + + // Update buffers. + *dst += decompr_size; + *dst_avail -= decompr_size; + + *src += compr_size; + *src_avail -= compr_size; + + return KNOT_EOK; +} + +static int rdata_traverse_parse(const uint8_t **src, size_t *src_avail, + uint8_t **dst, size_t *dst_avail, + const knot_rdata_descriptor_t *desc, + const uint8_t *pkt_wire) +{ + for (const int *type = desc->block_types; *type != KNOT_RDATA_WF_END; type++) { + int ret; + switch (*type) { + case KNOT_RDATA_WF_COMPRESSIBLE_DNAME: + case KNOT_RDATA_WF_DECOMPRESSIBLE_DNAME: + case KNOT_RDATA_WF_FIXED_DNAME: + ret = decompress_rdata_dname(src, src_avail, dst, dst_avail, + pkt_wire); + break; + case KNOT_RDATA_WF_NAPTR_HEADER: + ret = write_rdata_naptr_header(src, src_avail, dst, dst_avail); + break; + case KNOT_RDATA_WF_REMAINDER: + ret = write_rdata_fixed(src, src_avail, dst, dst_avail, *src_avail); + break; + default: + /* Fixed size block */ + assert(*type > 0); + ret = write_rdata_fixed(src, src_avail, dst, dst_avail, *type); + break; + } + if (ret != KNOT_EOK) { + return ret; + } + } + + return KNOT_EOK; +} + +static bool allow_zero_rdata(const knot_rrset_t *rr, + const knot_rdata_descriptor_t *desc) +{ + return rr->rclass != KNOT_CLASS_IN || // NONE and ANY for DDNS + rr->type == KNOT_RRTYPE_APL || // APL RR type + desc->type_name == NULL; // Unknown RR type +} + +static int parse_rdata(const uint8_t *pkt_wire, size_t *pos, size_t pkt_size, + knot_mm_t *mm, uint16_t rdlength, knot_rrset_t *rrset) +{ + assert(pkt_wire); + assert(pos); + assert(rrset); + + const knot_rdata_descriptor_t *desc = knot_get_rdata_descriptor(rrset->type); + if (desc->type_name == NULL) { + desc = knot_get_obsolete_rdata_descriptor(rrset->type); + } + + if (rdlength == 0) { + if (allow_zero_rdata(rrset, desc)) { + return knot_rrset_add_rdata(rrset, NULL, 0, mm); + } else { + return KNOT_EMALF; + } + } else if (pkt_size - *pos < rdlength) { + return KNOT_EMALF; + } + + // Buffer for parsed rdata (decompression extends rdata length). + const size_t max_rdata_len = UINT16_MAX; + uint8_t buf[knot_rdata_size(max_rdata_len)]; + knot_rdata_t *rdata = (knot_rdata_t *)buf; + + const uint8_t *src = pkt_wire + *pos; + size_t src_avail = rdlength; + uint8_t *dst = rdata->data; + size_t dst_avail = max_rdata_len; + + // Parse RDATA. + int ret = rdata_traverse_parse(&src, &src_avail, &dst, &dst_avail, desc, pkt_wire); + if (ret != KNOT_EOK) { + return KNOT_EMALF; + } + + // Check for trailing data. + size_t real_len = max_rdata_len - dst_avail; + if (real_len < rdlength) { + return KNOT_EMALF; + } + rdata->len = real_len; + + ret = knot_rdataset_add(&rrset->rrs, rdata, mm); + if (ret != KNOT_EOK) { + return ret; + } + + // Update position pointer. + *pos += rdlength; + + return KNOT_EOK; +} + +_public_ +int knot_rrset_rr_from_wire(const uint8_t *wire, size_t *pos, size_t max_size, + knot_rrset_t *rrset, knot_mm_t *mm, bool canonical) +{ + if (wire == NULL || pos == NULL || *pos > max_size || rrset == NULL) { + return KNOT_EINVAL; + } + + uint16_t rdlen = 0; + int ret = parse_header(wire, pos, max_size, mm, rrset, &rdlen); + if (ret != KNOT_EOK) { + return ret; + } + + ret = parse_rdata(wire, pos, max_size, mm, rdlen, rrset); + if (ret != KNOT_EOK) { + knot_rrset_clear(rrset, mm); + return ret; + } + + // Convert RR to the canonical format. + if (canonical) { + ret = knot_rrset_rr_to_canonical(rrset); + if (ret != KNOT_EOK) { + knot_rrset_clear(rrset, mm); + } + } + + return KNOT_EOK; +} diff --git a/src/libknot/packet/rrset-wire.h b/src/libknot/packet/rrset-wire.h new file mode 100644 index 0000000..e4370fd --- /dev/null +++ b/src/libknot/packet/rrset-wire.h @@ -0,0 +1,73 @@ +/* Copyright (C) 2018 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz> + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. + */ +/*! + * \file + * + * \brief RRSet from/to wire conversion functions. + * + * \addtogroup wire + * @{ + */ + +#pragma once + +#include "libknot/rrset.h" +#include "libknot/packet/compr.h" + +/*! + * \brief Write RR Set content to a wire. + * + * \param rrset RRSet to be converted. + * \param wire Output wire buffer. + * \param max_size Capacity of wire buffer. + * \param rotate Rotate the RR order by this count. + * \param compr Compression context. + * \param flags Flags; currently only KNOT_PF_TTL_ORIG is accepted. + * + * \return Output size, negative number on error (KNOT_E*). + */ +int knot_rrset_to_wire_extra(const knot_rrset_t *rrset, uint8_t *wire, + uint16_t max_size, uint16_t rotate, + knot_compr_t *compr, uint16_t flags); + +/* TODO: remove in next major version. */ +int knot_rrset_to_wire_rotate(const knot_rrset_t *rrset, uint8_t *wire, + uint16_t max_size, uint16_t rotate, + knot_compr_t *compr); + +/*! \brief Same as knot_rrset_to_wire_extra but without rrset rotation and flags. */ +static inline int knot_rrset_to_wire(const knot_rrset_t *rrset, uint8_t *wire, + uint16_t max_size, knot_compr_t *compr) +{ + return knot_rrset_to_wire_extra(rrset, wire, max_size, 0, compr, 0); +} + +/*! +* \brief Creates one RR from wire, stores it into \a rrset. +* +* \param wire Source wire (the whole packet). +* \param pos Position in \a wire where to start parsing. +* \param max_size Total size of data in \a wire (size of the packet). +* \param rrset Destination RRSet. +* \param mm Memory context. +* \param canonical Convert rrset to canonical format indication. +* +* \return KNOT_E* +*/ +int knot_rrset_rr_from_wire(const uint8_t *wire, size_t *pos, size_t max_size, + knot_rrset_t *rrset, knot_mm_t *mm, bool canonical); + +/*! @} */ diff --git a/src/libknot/packet/wire.h b/src/libknot/packet/wire.h new file mode 100644 index 0000000..26bc80e --- /dev/null +++ b/src/libknot/packet/wire.h @@ -0,0 +1,980 @@ +/* Copyright (C) 2018 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz> + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. + */ +/*! + * \file + * + * \brief Functions for manipulating and parsing raw data in DNS packets. + * + * \addtogroup wire + * @{ + */ + +#pragma once + +#include <assert.h> +#include <stdint.h> + +#include "libknot/attribute.h" +#include "libknot/wire.h" + +/*! \brief Offset of DNS header fields in wireformat. */ +enum knot_wire_offsets { + KNOT_WIRE_OFFSET_ID = 0, + KNOT_WIRE_OFFSET_FLAGS1 = 2, + KNOT_WIRE_OFFSET_FLAGS2 = 3, + KNOT_WIRE_OFFSET_QDCOUNT = 4, + KNOT_WIRE_OFFSET_ANCOUNT = 6, + KNOT_WIRE_OFFSET_NSCOUNT = 8, + KNOT_WIRE_OFFSET_ARCOUNT = 10 +}; + +/*! \brief Minimum size for some parts of the DNS packet. */ +enum knot_wire_sizes { + KNOT_WIRE_HEADER_SIZE = 12, + KNOT_WIRE_QUESTION_MIN_SIZE = 5, + KNOT_WIRE_RR_MIN_SIZE = 11, + KNOT_WIRE_MIN_PKTSIZE = 512, + KNOT_WIRE_MAX_PKTSIZE = 65535, + KNOT_WIRE_MAX_PAYLOAD = KNOT_WIRE_MAX_PKTSIZE + - KNOT_WIRE_HEADER_SIZE + - KNOT_WIRE_QUESTION_MIN_SIZE +}; + +/* + * Packet header manipulation functions. + */ + +/*! + * \brief Returns the ID from wire format of the packet. + * + * \param packet Wire format of the packet. + * + * \return DNS packet ID. + */ +static inline uint16_t knot_wire_get_id(const uint8_t *packet) +{ + return knot_wire_read_u16(packet + KNOT_WIRE_OFFSET_ID); +} + +/*! + * \brief Sets the ID to the wire format of the packet. + * + * \param packet Wire format of the packet. + * \param id DNS packet ID. + */ +static inline void knot_wire_set_id(uint8_t *packet, uint16_t id) +{ + knot_wire_write_u16(packet + KNOT_WIRE_OFFSET_ID, id); +} + +/*! + * \brief Returns the first byte of flags from wire format of the packet. + * + * \param packet Wire format of the packet. + * + * \return First byte of DNS flags. + */ +static inline uint8_t knot_wire_get_flags1(const uint8_t *packet) +{ + return *(packet + KNOT_WIRE_OFFSET_FLAGS1); +} + +/*! + * \brief Sets the first byte of flags to the wire format of the packet. + * + * \param packet Wire format of the packet. + * \param flags1 First byte of the DNS flags. + */ +static inline uint8_t knot_wire_set_flags1(uint8_t *packet, uint8_t flags1) +{ + return *(packet + KNOT_WIRE_OFFSET_FLAGS1) = flags1; +} + +/*! + * \brief Returns the second byte of flags from wire format of the packet. + * + * \param packet Wire format of the packet. + * + * \return Second byte of DNS flags. + */ +static inline uint8_t knot_wire_get_flags2(const uint8_t *packet) +{ + return *(packet + KNOT_WIRE_OFFSET_FLAGS2); +} + +/*! + * \brief Sets the second byte of flags to the wire format of the packet. + * + * \param packet Wire format of the packet. + * \param flags2 Second byte of the DNS flags. + */ +static inline uint8_t knot_wire_set_flags2(uint8_t *packet, uint8_t flags2) +{ + return *(packet + KNOT_WIRE_OFFSET_FLAGS2) = flags2; +} + +/*! + * \brief Returns the QDCOUNT (count of Question entries) from wire format of + * the packet. + * + * \param packet Wire format of the packet. + * + * \return QDCOUNT (count of Question entries in the packet). + */ +static inline uint16_t knot_wire_get_qdcount(const uint8_t *packet) +{ + return knot_wire_read_u16(packet + KNOT_WIRE_OFFSET_QDCOUNT); +} + +/*! + * \brief Sets the QDCOUNT (count of Question entries) to wire format of the + * packet. + * + * \param packet Wire format of the packet. + * \param qdcount QDCOUNT (count of Question entries in the packet). + */ +static inline void knot_wire_set_qdcount(uint8_t *packet, uint16_t qdcount) +{ + knot_wire_write_u16(packet + KNOT_WIRE_OFFSET_QDCOUNT, qdcount); +} + +/*! + * \brief Adds to QDCOUNT. + */ +static inline void knot_wire_add_qdcount(uint8_t *packet, int16_t n) +{ + knot_wire_write_u16(packet + KNOT_WIRE_OFFSET_QDCOUNT, + knot_wire_get_qdcount(packet) + n); +} + +/*! + * \brief Returns the ANCOUNT (count of Answer entries) from wire format of + * the packet. + * + * \param packet Wire format of the packet. + * + * \return ANCOUNT (count of Answer entries in the packet). + */ +static inline uint16_t knot_wire_get_ancount(const uint8_t *packet) +{ + return knot_wire_read_u16(packet + KNOT_WIRE_OFFSET_ANCOUNT); +} + +/*! + * \brief Sets the ANCOUNT (count of Answer entries) to wire format of the + * packet. + * + * \param packet Wire format of the packet. + * \param ancount ANCOUNT (count of Answer entries in the packet). + */ +static inline void knot_wire_set_ancount(uint8_t *packet, uint16_t ancount) +{ + knot_wire_write_u16(packet + KNOT_WIRE_OFFSET_ANCOUNT, ancount); +} + +/*! + * \brief Adds to ANCOUNT. + */ +static inline void knot_wire_add_ancount(uint8_t *packet, int16_t n) +{ + knot_wire_write_u16(packet + KNOT_WIRE_OFFSET_ANCOUNT, + knot_wire_get_ancount(packet) + n); +} + +/*! + * \brief Returns the NSCOUNT (count of Authority entries) from wire format of + * the packet. + * + * \param packet Wire format of the packet. + * + * \return NSCOUNT (count of Authority entries in the packet). + */ +static inline uint16_t knot_wire_get_nscount(const uint8_t *packet) +{ + return knot_wire_read_u16(packet + KNOT_WIRE_OFFSET_NSCOUNT); +} + +/*! + * \brief Sets the NSCOUNT (count of Authority entries) to wire format of the + * packet. + * + * \param packet Wire format of the packet. + * \param nscount NSCOUNT (count of Authority entries in the packet). + */ +static inline void knot_wire_set_nscount(uint8_t *packet, uint16_t nscount) +{ + knot_wire_write_u16(packet + KNOT_WIRE_OFFSET_NSCOUNT, nscount); +} + +/*! + * \brief Adds to NSCOUNT. + */ +static inline void knot_wire_add_nscount(uint8_t *packet, int16_t n) +{ + knot_wire_write_u16(packet + KNOT_WIRE_OFFSET_NSCOUNT, + knot_wire_get_nscount(packet) + n); +} + +/*! + * \brief Returns the ARCOUNT (count of Additional entries) from wire format of + * the packet. + * + * \param packet Wire format of the packet. + * + * \return ARCOUNT (count of Additional entries in the packet). + */ +static inline uint16_t knot_wire_get_arcount(const uint8_t *packet) +{ + return knot_wire_read_u16(packet + KNOT_WIRE_OFFSET_ARCOUNT); +} + +/*! + * \brief Sets the ARCOUNT (count of Additional entries) to wire format of the + * packet. + * + * \param packet Wire format of the packet. + * \param arcount ARCOUNT (count of Additional entries in the packet). + */ +static inline void knot_wire_set_arcount(uint8_t *packet, uint16_t arcount) +{ + knot_wire_write_u16(packet + KNOT_WIRE_OFFSET_ARCOUNT, arcount); +} + +/*! + * \brief Adds to ARCOUNT. + */ +static inline void knot_wire_add_arcount(uint8_t *packet, int16_t n) +{ + knot_wire_write_u16(packet + KNOT_WIRE_OFFSET_ARCOUNT, + knot_wire_get_arcount(packet) + n); +} + +/* + * Packet header flags manipulation functions. + */ +/*! \brief Constants for DNS header flags in the first flags byte. */ +enum knot_wire_flags1_consts { + KNOT_WIRE_RD_MASK = (uint8_t)0x01U, /*!< RD bit mask. */ + KNOT_WIRE_RD_SHIFT = 0, /*!< RD bit shift. */ + KNOT_WIRE_TC_MASK = (uint8_t)0x02U, /*!< TC bit mask. */ + KNOT_WIRE_TC_SHIFT = 1, /*!< TC bit shift. */ + KNOT_WIRE_AA_MASK = (uint8_t)0x04U, /*!< AA bit mask. */ + KNOT_WIRE_AA_SHIFT = 2, /*!< AA bit shift. */ + KNOT_WIRE_OPCODE_MASK = (uint8_t)0x78U, /*!< OPCODE mask. */ + KNOT_WIRE_OPCODE_SHIFT = 3, /*!< OPCODE shift. */ + KNOT_WIRE_QR_MASK = (uint8_t)0x80U, /*!< QR bit mask. */ + KNOT_WIRE_QR_SHIFT = 7 /*!< QR bit shift. */ +}; + +/*! \brief Constants for DNS header flags in the second flags byte. */ +enum knot_wire_flags2_consts { + KNOT_WIRE_RCODE_MASK = (uint8_t)0x0fU, /*!< RCODE mask. */ + KNOT_WIRE_RCODE_SHIFT = 0, /*!< RCODE shift. */ + KNOT_WIRE_CD_MASK = (uint8_t)0x10U, /*!< CD bit mask. */ + KNOT_WIRE_CD_SHIFT = 4, /*!< CD bit shift. */ + KNOT_WIRE_AD_MASK = (uint8_t)0x20U, /*!< AD bit mask. */ + KNOT_WIRE_AD_SHIFT = 5, /*!< AD bit shift. */ + KNOT_WIRE_Z_MASK = (uint8_t)0x40U, /*!< Zero bit mask. */ + KNOT_WIRE_Z_SHIFT = 6, /*!< Zero bit shift. */ + KNOT_WIRE_RA_MASK = (uint8_t)0x80U, /*!< RA bit mask. */ + KNOT_WIRE_RA_SHIFT = 7 /*!< RA bit shift. */ +}; + +/* + * Functions for getting / setting / clearing flags and codes directly in packet + */ + +/*! + * \brief Returns the RD bit from wire format of the packet. + * + * \param packet Wire format of the packet. + * + * \return Flags with only the RD bit according to its setting in the packet. + */ +static inline uint8_t knot_wire_get_rd(const uint8_t *packet) +{ + return *(packet + KNOT_WIRE_OFFSET_FLAGS1) & KNOT_WIRE_RD_MASK; +} + +/*! + * \brief Sets the RD bit in the wire format of the packet. + * + * \param packet Wire format of the packet. + */ +static inline void knot_wire_set_rd(uint8_t *packet) +{ + *(packet + KNOT_WIRE_OFFSET_FLAGS1) |= KNOT_WIRE_RD_MASK; +} + +/*! + * \brief Clears the RD bit in the wire format of the packet. + * + * \param packet Wire format of the packet. + */ +static inline void knot_wire_clear_rd(uint8_t *packet) +{ + *(packet + KNOT_WIRE_OFFSET_FLAGS1) &= ~KNOT_WIRE_RD_MASK; +} + +/*! + * \brief Returns the TC bit from wire format of the packet. + * + * \param packet Wire format of the packet. + * + * \return Flags with only the TC bit according to its setting in the packet. + */ +static inline uint8_t knot_wire_get_tc(const uint8_t *packet) +{ + return *(packet + KNOT_WIRE_OFFSET_FLAGS1) & KNOT_WIRE_TC_MASK; +} + +/*! + * \brief Sets the TC bit in the wire format of the packet. + * + * \param packet Wire format of the packet. + */ +static inline void knot_wire_set_tc(uint8_t *packet) +{ + *(packet + KNOT_WIRE_OFFSET_FLAGS1) |= KNOT_WIRE_TC_MASK; +} + +/*! + * \brief Clears the TC bit in the wire format of the packet. + * + * \param packet Wire format of the packet. + */ +static inline void knot_wire_clear_tc(uint8_t *packet) +{ + *(packet + KNOT_WIRE_OFFSET_FLAGS1) &= ~KNOT_WIRE_TC_MASK; +} + +/*! + * \brief Returns the AA bit from wire format of the packet. + * + * \param packet Wire format of the packet. + * + * \return Flags with only the AA bit according to its setting in the packet. + */ +static inline uint8_t knot_wire_get_aa(const uint8_t *packet) +{ + return *(packet + KNOT_WIRE_OFFSET_FLAGS1) & KNOT_WIRE_AA_MASK; +} + +/*! + * \brief Sets the AA bit in the wire format of the packet. + * + * \param packet Wire format of the packet. + */ +static inline void knot_wire_set_aa(uint8_t *packet) +{ + *(packet + KNOT_WIRE_OFFSET_FLAGS1) |= KNOT_WIRE_AA_MASK; +} + +/*! + * \brief Clears the AA bit in the wire format of the packet. + * + * \param packet Wire format of the packet. + */ +static inline void knot_wire_clear_aa(uint8_t *packet) +{ + *(packet + KNOT_WIRE_OFFSET_FLAGS1) &= ~KNOT_WIRE_AA_MASK; +} + +/*! + * \brief Returns the OPCODE from wire format of the packet. + * + * \param packet Wire format of the packet. + * + * \return OPCODE of the packet. + */ +static inline uint8_t knot_wire_get_opcode(const uint8_t *packet) +{ + return (*(packet + KNOT_WIRE_OFFSET_FLAGS1) + & KNOT_WIRE_OPCODE_MASK) >> KNOT_WIRE_OPCODE_SHIFT; +} + +/*! + * \brief Sets the OPCODE in the wire format of the packet. + * + * \param packet Wire format of the packet. + * \param opcode OPCODE to set. + */ +static inline void knot_wire_set_opcode(uint8_t *packet, short opcode) +{ + uint8_t *flags1 = packet + KNOT_WIRE_OFFSET_FLAGS1; + *flags1 = (*flags1 & ~KNOT_WIRE_OPCODE_MASK) + | ((opcode) << KNOT_WIRE_OPCODE_SHIFT); +} + +/*! + * \brief Returns the QR bit from wire format of the packet. + * + * \param packet Wire format of the packet. + * + * \return Nonzero for responses and zero for queries. + */ +static inline uint8_t knot_wire_get_qr(const uint8_t *packet) +{ + return *(packet + KNOT_WIRE_OFFSET_FLAGS1) & KNOT_WIRE_QR_MASK; +} + +/*! + * \brief Sets the QR bit in the wire format of the packet. + * + * \param packet Wire format of the packet. + */ +static inline void knot_wire_set_qr(uint8_t *packet) +{ + *(packet + KNOT_WIRE_OFFSET_FLAGS1) |= KNOT_WIRE_QR_MASK; +} + +/*! + * \brief Clears the QR bit in the wire format of the packet. + * + * \param packet Wire format of the packet. + */ +static inline void knot_wire_clear_qr(uint8_t *packet) +{ + *(packet + KNOT_WIRE_OFFSET_FLAGS1) &= ~KNOT_WIRE_QR_MASK; +} + +/*! + * \brief Returns the RCODE from wire format of the packet. + * + * \param packet Wire format of the packet. + * + * \return RCODE of the packet. + */ +static inline uint8_t knot_wire_get_rcode(const uint8_t *packet) +{ + return *(packet + KNOT_WIRE_OFFSET_FLAGS2) + & KNOT_WIRE_RCODE_MASK; +} + +/*! + * \brief Sets the RCODE in the wire format of the packet. + * + * \param packet Wire format of the packet. + * \param rcode RCODE to set. + */ +static inline void knot_wire_set_rcode(uint8_t *packet, short rcode) +{ + uint8_t *flags2 = packet + KNOT_WIRE_OFFSET_FLAGS2; + *flags2 = (*flags2 & ~KNOT_WIRE_RCODE_MASK) | (rcode); +} + +/*! + * \brief Returns the CD bit from wire format of the packet. + * + * \param packet Wire format of the packet. + * + * \return Flags with only the CD bit according to its setting in the packet. + */ +static inline uint8_t knot_wire_get_cd(const uint8_t *packet) +{ + return *(packet + KNOT_WIRE_OFFSET_FLAGS2) & KNOT_WIRE_CD_MASK; +} + +/*! + * \brief Sets the CD bit in the wire format of the packet. + * + * \param packet Wire format of the packet. + */ +static inline void knot_wire_set_cd(uint8_t *packet) +{ + *(packet + KNOT_WIRE_OFFSET_FLAGS2) |= KNOT_WIRE_CD_MASK; +} + +/*! + * \brief Clears the CD bit in the wire format of the packet. + * + * \param packet Wire format of the packet. + */ +static inline void knot_wire_clear_cd(uint8_t *packet) +{ + *(packet + KNOT_WIRE_OFFSET_FLAGS2) &= ~KNOT_WIRE_CD_MASK; +} + +/*! + * \brief Returns the AD bit from wire format of the packet. + * + * \param packet Wire format of the packet. + * + * \return Flags with only the AD bit according to its setting in the packet. + */ +static inline uint8_t knot_wire_get_ad(const uint8_t *packet) +{ + return *(packet + KNOT_WIRE_OFFSET_FLAGS2) & KNOT_WIRE_AD_MASK; +} + +/*! + * \brief Sets the AD bit in the wire format of the packet. + * + * \param packet Wire format of the packet. + */ +static inline void knot_wire_set_ad(uint8_t *packet) +{ + *(packet + KNOT_WIRE_OFFSET_FLAGS2) |= KNOT_WIRE_AD_MASK; +} + +/*! + * \brief Clears the AD bit in the wire format of the packet. + * + * \param packet Wire format of the packet. + */ +static inline void knot_wire_clear_ad(uint8_t *packet) +{ + *(packet + KNOT_WIRE_OFFSET_FLAGS2) &= ~KNOT_WIRE_AD_MASK; +} + +/*! + * \brief Returns the Zero bit from wire format of the packet. + * + * \param packet Wire format of the packet. + * + * \return Flags with only the Zero bit according to its setting in the packet. + */ +static inline uint8_t knot_wire_get_z(const uint8_t *packet) +{ + return *(packet + KNOT_WIRE_OFFSET_FLAGS2) & KNOT_WIRE_Z_MASK; +} + +/*! + * \brief Sets the Zero bit in the wire format of the packet. + * + * \param packet Wire format of the packet. + */ +static inline void knot_wire_set_z(uint8_t *packet) +{ + *(packet + KNOT_WIRE_OFFSET_FLAGS2) |= KNOT_WIRE_Z_MASK; +} + +/*! + * \brief Clears the Zero bit in the wire format of the packet. + * + * \param packet Wire format of the packet. + */ +static inline void knot_wire_clear_z(uint8_t *packet) +{ + *(packet + KNOT_WIRE_OFFSET_FLAGS2) &= ~KNOT_WIRE_Z_MASK; +} + +/*! + * \brief Returns the RA bit from wire format of the packet. + * + * \param packet Wire format of the packet. + * + * \return Flags with only the RA bit according to its setting in the packet. + */ +static inline uint8_t knot_wire_get_ra(const uint8_t *packet) +{ + return *(packet + KNOT_WIRE_OFFSET_FLAGS2) & KNOT_WIRE_RA_MASK; +} + +/*! + * \brief Sets the RA bit in the wire format of the packet. + * + * \param packet Wire format of the packet. + */ +static inline void knot_wire_set_ra(uint8_t *packet) +{ + *(packet + KNOT_WIRE_OFFSET_FLAGS2) |= KNOT_WIRE_RA_MASK; +} + +/*! + * \brief Clears the RA bit in the wire format of the packet. + * + * \param packet Wire format of the packet. + */ +static inline void knot_wire_clear_ra(uint8_t *packet) +{ + *(packet + KNOT_WIRE_OFFSET_FLAGS2) &= ~KNOT_WIRE_RA_MASK; +} + +/* + * Functions for getting / setting / clearing flags in flags variable + */ + +/*! + * \brief Returns the RD bit from the first byte of flags. + * + * \param flags1 First byte of DNS header flags. + * + * \return Flags byte with only the RD bit according to its setting in + * \a flags1. + */ +static inline uint8_t knot_wire_flags_get_rd(uint8_t flags1) +{ + return flags1 & KNOT_WIRE_RD_MASK; +} + +/*! + * \brief Sets the RD bit in the first byte of flags. + * + * \param flags1 First byte of DNS header flags. + */ +static inline void knot_wire_flags_set_rd(uint8_t *flags1) +{ + *flags1 |= KNOT_WIRE_RD_MASK; +} + +/*! + * \brief Clears the RD bit in the first byte of flags. + * + * \param flags1 First byte of DNS header flags. + */ +static inline void knot_wire_flags_clear_rd(uint8_t *flags1) +{ + *flags1 &= ~KNOT_WIRE_RD_MASK; +} + +/*! + * \brief Returns the TC bit from the first byte of flags. + * + * \param flags1 First byte of DNS header flags. + * + * \return Flags byte with only the TC bit according to its setting in + * \a flags1. + */ +static inline uint8_t knot_wire_flags_get_tc(uint8_t flags1) +{ + return flags1 & KNOT_WIRE_TC_MASK; +} + +/*! + * \brief Sets the TC bit in the first byte of flags. + * + * \param flags1 First byte of DNS header flags. + */ +static inline void knot_wire_flags_set_tc(uint8_t *flags1) +{ + *flags1 |= KNOT_WIRE_TC_MASK; +} + +/*! + * \brief Clears the TC bit in the first byte of flags. + * + * \param flags1 First byte of DNS header flags. + */ +static inline void knot_wire_flags_clear_tc(uint8_t *flags1) +{ + *flags1 &= ~KNOT_WIRE_TC_MASK; +} + +/*! + * \brief Returns the AA bit from the first byte of flags. + * + * \param flags1 First byte of DNS header flags. + * + * \return Flags byte with only the AA bit according to its setting in + * \a flags1. + */ +static inline uint8_t knot_wire_flags_get_aa(uint8_t flags1) +{ + return flags1 & KNOT_WIRE_AA_MASK; +} + +/*! + * \brief Sets the AA bit in the first byte of flags. + * + * \param flags1 First byte of DNS header flags. + */ +static inline void knot_wire_flags_set_aa(uint8_t *flags1) +{ + *flags1 |= KNOT_WIRE_AA_MASK; +} + +/*! + * \brief Clears the AA bit in the first byte of flags. + * + * \param flags1 First byte of DNS header flags. + */ +static inline void knot_wire_flags_clear_aa(uint8_t *flags1) +{ + *flags1 &= ~KNOT_WIRE_AA_MASK; +} + +/*! + * \brief Returns the OPCODE from the first byte of flags. + * + * \param flags1 First byte of DNS header flags. + * + * \return OPCODE + */ +static inline uint8_t knot_wire_flags_get_opcode(uint8_t flags1) +{ + return (flags1 & KNOT_WIRE_OPCODE_MASK) + >> KNOT_WIRE_OPCODE_SHIFT; +} + +/*! + * \brief Sets the OPCODE in the first byte of flags. + * + * \param flags1 First byte of DNS header flags. + * \param opcode OPCODE to set. + */ +static inline void knot_wire_flags_set_opcode(uint8_t *flags1, short opcode) +{ + *flags1 = (*flags1 & ~KNOT_WIRE_OPCODE_MASK) + | ((opcode) << KNOT_WIRE_OPCODE_SHIFT); +} + +/*! + * \brief Returns the QR bit from the first byte of flags. + * + * \param flags1 First byte of DNS header flags. + * + * \return Flags byte with only the QR bit according to its setting in + * \a flags1. + */ +static inline uint8_t knot_wire_flags_get_qr(uint8_t flags1) +{ + return flags1 & KNOT_WIRE_QR_MASK; +} + +/*! + * \brief Sets the QR bit in the first byte of flags. + * + * \param flags1 First byte of DNS header flags. + */ +static inline void knot_wire_flags_set_qr(uint8_t *flags1) +{ + *flags1 |= KNOT_WIRE_QR_MASK; +} + +/*! + * \brief Clears the QR bit in the first byte of flags. + * + * \param flags1 First byte of DNS header flags. + */ +static inline void knot_wire_flags_clear_qr(uint8_t *flags1) +{ + *flags1 &= ~KNOT_WIRE_QR_MASK; +} + +/*! + * \brief Returns the RCODE from the second byte of flags. + * + * \param flags2 First byte of DNS header flags. + * + * \return RCODE + */ +static inline uint8_t knot_wire_flags_get_rcode(uint8_t flags2) +{ + return flags2 & KNOT_WIRE_RCODE_MASK; +} + +/*! + * \brief Sets the RCODE in the second byte of flags. + * + * \param flags2 Second byte of DNS header flags. + * \param rcode RCODE to set. + */ +static inline void knot_wire_flags_set_rcode(uint8_t *flags2, short rcode) +{ + *flags2 = (*flags2 & ~KNOT_WIRE_RCODE_MASK) | (rcode); +} + +/*! + * \brief Returns the CD bit from the second byte of flags. + * + * \param flags2 Second byte of DNS header flags. + * + * \return Flags byte with only the CD bit according to its setting in + * \a flags2. + */ +static inline uint8_t knot_wire_flags_get_cd(uint8_t flags2) +{ + return flags2 & KNOT_WIRE_CD_MASK; +} + +/*! + * \brief Sets the CD bit in the second byte of flags. + * + * \param flags2 Second byte of DNS header flags. + */ +static inline void knot_wire_flags_set_cd(uint8_t *flags2) +{ + *flags2 |= KNOT_WIRE_CD_MASK; +} + +/*! + * \brief Clears the CD bit in the second byte of flags. + * + * \param flags2 Second byte of DNS header flags. + */ +static inline void knot_wire_flags_clear_cd(uint8_t *flags2) +{ + *flags2 &= ~KNOT_WIRE_CD_MASK; +} + +/*! + * \brief Returns the AD bit from the second byte of flags. + * + * \param flags2 Second byte of DNS header flags. + * + * \return Flags byte with only the AD bit according to its setting in + * \a flags2. + */ +static inline uint8_t knot_wire_flags_get_ad(uint8_t flags2) +{ + return flags2 & KNOT_WIRE_AD_MASK; +} + +/*! + * \brief Sets the AD bit in the second byte of flags. + * + * \param flags2 Second byte of DNS header flags. + */ +static inline void knot_wire_flags_set_ad(uint8_t *flags2) +{ + *flags2 |= KNOT_WIRE_AD_MASK; +} + +/*! + * \brief Clears the AD bit in the second byte of flags. + * + * \param flags2 Second byte of DNS header flags. + */ +static inline void knot_wire_flags_clear_ad(uint8_t *flags2) +{ + *flags2 &= ~KNOT_WIRE_AD_MASK; +} + +/*! + * \brief Returns the Zero bit from the second byte of flags. + * + * \param flags2 Second byte of DNS header flags. + * + * \return Flags byte with only the Zero bit according to its setting in + * \a flags2. + */ +static inline uint8_t knot_wire_flags_get_z(uint8_t flags2) +{ + return flags2 & KNOT_WIRE_Z_MASK; +} + +/*! + * \brief Sets the Zero bit in the second byte of flags. + * + * \param flags2 Second byte of DNS header flags. + */ +static inline void knot_wire_flags_set_z(uint8_t *flags2) +{ + *flags2 |= KNOT_WIRE_Z_MASK; +} + +/*! + * \brief Clears the Zero bit in the second byte of flags. + * + * \param flags2 Second byte of DNS header flags. + */ +static inline void knot_wire_flags_clear_z(uint8_t *flags2) +{ + *flags2 &= ~KNOT_WIRE_Z_MASK; +} + +/*! + * \brief Returns the RA bit from the second byte of flags. + * + * \param flags2 Second byte of DNS header flags. + * + * \return Flags byte with only the RA bit according to its setting in + * \a flags2. + */ +static inline uint8_t knot_wire_flags_get_ra(uint8_t flags2) +{ + return flags2 & KNOT_WIRE_RA_MASK; +} + +/*! + * \brief Sets the RA bit in the second byte of flags. + * + * \param flags2 Second byte of DNS header flags. + */ +static inline void knot_wire_flags_set_ra(uint8_t *flags2) +{ + *flags2 |= KNOT_WIRE_RA_MASK; +} + +/*! + * \brief Clears the RA bit in the second byte of flags. + * + * \param flags2 Second byte of DNS header flags. + */ +static inline void knot_wire_flags_clear_ra(uint8_t *flags2) +{ + *flags2 &= ~KNOT_WIRE_RA_MASK; +} + +/* + * Pointer manipulation + */ + +enum knot_wire_pointer_consts { + /*! \brief DNS packet pointer designation (first two bits set to 1). */ + KNOT_WIRE_PTR = (uint8_t)0xC0, + /*! \brief DNS packet minimal pointer (KNOT_WIRE_PTR + 1 zero byte). */ + KNOT_WIRE_PTR_BASE = (uint16_t)0xC000, + /*! \brief DNS packet maximal offset (KNOT_WIRE_BASE complement). */ + KNOT_WIRE_PTR_MAX = (uint16_t)0x3FFF +}; + +static inline int knot_wire_is_pointer(const uint8_t *pos) +{ + return pos && ((pos[0] & KNOT_WIRE_PTR) == KNOT_WIRE_PTR); +} + +/*! + * \brief Creates a DNS packet pointer and stores it in wire format. + * + * \param pos Position where tu put the pointer. + * \param ptr Relative position of the item to which the pointer should point in + * the wire format of the packet. + */ +static inline void knot_wire_put_pointer(uint8_t *pos, uint16_t ptr) +{ + knot_wire_write_u16(pos, ptr); // Write pointer offset. + assert((pos[0] & KNOT_WIRE_PTR) == 0); // Check for maximal offset. + pos[0] |= KNOT_WIRE_PTR; // Add pointer mark. +} + +static inline uint16_t knot_wire_get_pointer(const uint8_t *pos) +{ + assert(knot_wire_is_pointer(pos)); // Check pointer. + return (knot_wire_read_u16(pos) - KNOT_WIRE_PTR_BASE); // Return offset. +} + +_pure_ _mustcheck_ +static inline const uint8_t *knot_wire_seek_label(const uint8_t *lp, const uint8_t *wire) +{ + while (knot_wire_is_pointer(lp)) { + if (!wire) + return NULL; + lp = wire + knot_wire_get_pointer(lp); + } + return lp; +} + +_pure_ _mustcheck_ +static inline const uint8_t *knot_wire_next_label(const uint8_t *lp, const uint8_t *wire) +{ + if (!lp || !lp[0]) /* No label after final label. */ + return NULL; + return knot_wire_seek_label(lp + (lp[0] + sizeof(uint8_t)), wire); +} + +/*! @} */ |